Absorption refrigeration



Patented May 19, 1936 UNITED STATES PATENT OFFICE No Drawing.Application May 3, 1935, Serial No. 19,600

2 Claims.

The present invention relates generally to a solvent material and arefrigerant mixture for absorption refrigerating machines, both of thetwo-fluid type and of the three-fluid type.

In absorption refrigeration there is required a solvent material adaptedto remain liquid throughout the operation of the apparatus, and arefrigerant material adapted to have a liquid and a vapor phase in thecycles of operation, adapted to be dissolved or absorbed in the solvent,adapted to be evaporated or boiled as a vapor from the solvent mixtureand from the solvent, and adapted to be condensed from the vapor to aliquid. Numerous refrigerants and numerous solvents are known, as wellas successful combinatlons of these.

The two-fluid absorption machines have certain mechanical parts whichmay be omitted or which are not duplicated in three-fluid machines. In athree-fluid machine, there is in addition to the two-fluid mixture abody of inert gas which is always gas, and which does not to anysubstantial extent dissolve in any of the components of the two-fluidcomposition, or in mixtures thereof.

The present invention is directed to a new solvent for absorptionrefrigeration, and to combinations thereof with refrigerants.

A particular object of the invention is the use of di-tetrahydrofurfurylether of diethylene glycol as a solvent.

Another object is the use of a combination of said solvent with therefrigerant, dichloromonofluoromethane.

Examples of the two-fluid apparatus in which the new solvent materialand the new combination may be used is disclosed in my co-pendingapplication Serial No. 651,306, filed January 12, 1933, or in my U. S.Patent No. 1,895,698, issued January 31, 1933. Other examples mayreadilybe cited, and will be known to those skilled in the art.

The two-fluid apparatus above referred to, briefly described, comprisesa still in which a liquid mixture of solvent and refrigerant is heatedto distill away as a vapor the refrigerant material, a condenser whereinsaid vapor is condensed to a liquid'state, an evaporator wherein theresulting liquid is vaporized at reduced pressure to producerefrigeration, and an absorber in which vapor of the refrigerantmaterial containing added heat unitsdacquired in the refrigeratingprocess) is again dissolved in the solvent material. Suitable heatexchangi g and circulating means are included, and automatic controlsmay be provided.

The particular characteristics of such a machine are that the stilloperates at temperatures well above normal temperatures, such forexample at 210 F. to 250 F.; and that the cooling unit operates attemperatures lower than normal, such as from 15 F. to 50 F. Variousparts of the apparatus differ in the prevailing temperatures andpressures, and both pressure and temperature determine the physicalstate of the free refrigerant material, whether gaseous or liquid, anddetermine the solubility relations between the refrigerant and thesolvent material. It is, therefore, very important that the solvent andthe refrigerant materials be physically adapted for use as individualmaterials in certain places and for certain functions, and that they bemutually adapted for certain functions when they are in combination.Other qualities not essential to refrigeration, but pertinent topractical usage, control or limit the choice of solvent or refrigerant,such as odor, volatility, viscosity, heat capacity, boiling point,freezing point, chemical stability, reactivity, corrosive action,inflammability, toxicity, etc.

By considering the limitations herein set forth and suggested, I havebeen able to utilize ditetrahydrofurfuryl ether of diethylene glycol asa solvent, for practical usage, in combination with the refrigerant,dichloromonofluoromethane, which is little known. I

The new solvent is herein named as di-tetrahydrofurfuryl ether ofdiethylene glycol. In order to leave no doublt as to its identity, its

. structural formula is herein given:

(Cd-I10) CHaOCI-IzCHaOCI-IaCHaOCHa Cd-I70) The refrigerant hereinspecified is dichloromonofluoromethane. In order to leave no doubt as toits identity, its structural formula is herein given:

CHClzF In the accompanying claims the invention is set forth as acombination useful in absorption refrigeration. It is to be understoodthat a simple adulteration of the new solvent in its pure form, eitherby reason of commercial impurities, or by addition of lesser quantitiesof other material, useful also as solvent, is permitted, and such a.composition is intended to fall within the scope of the presentinvention.

What I claim is:

1. A refrigerant mixture for the absorption type of refrigerationapparatus consisting of di-tetrahydrofurfuryl ether of diethylene glycolas the essentially predominant solvent, and dichloro- .monofluoromethaneas a refrigerant.

2. A refrigerant mixture for the absorption type of refrigerationapparatus consisting of di-tetrahydrofurfuryl ether of diethylene glycolas the essentially predominant solvent, and a volatile chemically stablehalogenated hydrocarbon refrigerant soluble in said solvent.

' GLENN F. ZEILHOEFER.

